"The Mystery of the Blue Train" is a detective novel written by the renowned British author Agatha Christie. It was first published in 1928 and features her famous fictional detective, Hercule Poirot. The story revolves around the murder of a wealthy American heiress named Ruth Kettering, who is found strangled aboard the luxurious Blue Train traveling from Calais to Nice in France.Hercule Poirot becomes involved in solving the case when he meets Ruth Kettering's father, Rufus Van Aldin, who suspects that her estranged husband, Derek Kettering, is behind the murder to gain access to her inheritance. As Poirot investigates, he encounters a web of complex relationships, multiple suspects, and hidden motives among the passengers on the train. The novel combines elements of romance, intrigue, and mystery as Poirot unravels the truth behind the murder in his signature meticulous and methodical style."The Mystery of the Blue Train" is a classic example of Agatha Christie's detective fiction, known for its clever plot twists, intriguing characters, and the brilliant deductive skills of Hercule Poirot as he strives to solve the enigmatic crime.